Figure 1.

Poly (A) tail is required for SG formation. A to D, HeLa cells were co-transfected with the pFlag-CMV5/TO-BGG reporter plasmid and either pCMV-Myc, pCMV-5 × Myc-Pan2 or pCMV-5 × Myc-Pan2 D1083A. (A) β-globin mRNA was detected by northern blot analysis. (B) HeLa cells were treated with arsenite (0.5 mM) for 30 min and exogenous Pan2 and endogenous G3BP1 were detected by indirect immunofluorescence. (C) For quantitative analysis, the total intensity, size and number of SGs were calculated based on (B) using MetaMorph software. The quantitative value of SGs in the control cells was defined as 100%. (D) Proteins were analyzed by western blotting using the indicated antibodies. (E–H) HeLa cells were co-transfected with the pFlag-CMV5/TO-BGG reporter plasmid and luciferase siRNA or Caf1/POP2 siRNA. (E) β-globin mRNA was detected by northern blot analysis. (F) Proteins were analyzed by western blotting using the indicated antibodies. The leftmost three lanes, which analyzed 2-fold dilutions of HeLa cells extract, show that the conditions used for western blotting are semi-quantitative. (G) HeLa cells were treated with arsenite (0.5 mM) for 30 min, and endogenous G3BP1 was detected by indirect immunofluorescence. (H) For quantitative analysis, the total intensity, size and number of SGs were calculated based on Figure 1G using MetaMorph software. The quantitative value of SGs in luciferase siRNA-transfected cells was defined as 100%. Results are the average of three independent experiments and shown as means ± SD. **P < 0.01; ***P < 0.001.